"Shrews do not eat small insects. their metabolisms are so fast that they need to eat almost constantlyto keep from starving to death. (so they keep up a constant meal of worms, beetles, etc.) a diet of a few tiny insects at a time would not be enough to keep the shrew/bat alive, especially if it needed to climb back up the tree again between flights. (that is, unless the metabolism had slowed down considerably between the real shrew and the gliding shrew...) also, bats do not eat tiny swarms of insects. for such a diet, the creature would need a huge, wide mouth, like that of the whipoorwill; no modern bats that I know of have such a diet: all either chase moths and mosquitoes around using their sonar, or eat fruit/drink nectar/blood. 2: the gliding squirrel has a long, flat tail used as a rudder; the shrew fhas a skinny, worthless tail, and the bat has almost none at all (it serves only as a prop for the membrane). without the ability such a tail would provide for quick adjusments in mid-flight, the bat may or may not have been able to survive. I don't know."

He was responding to this
"Quote:
Originally Posted by the_cloaked_crusader
here's a big hole in the evolutionary theory (at least for me) and I want to see if anyone here can fill it.
am I correct in thinking that bats are supposed to have evolved from a shrew-like mammal? if so, I don't see how the transitional forms could survive, since for the paws to become wings they would have to go through many stages in which they would be useless for walking, flying, and catching food--as the "fingers" grew longer and longer, the creature would be unable to properly hunt and escape from predators until its wings were developed enough for it to fly. am I missing something here?
This isn't a "big hole", but a restatement of Mivart's question in the 1860s: What use is half a wing? Mivart used it for birds. You are using it on bats. You are helped by the paucity of the fossil record for bats because their bones are so fragile and they live in generally arid climates. Combined, this means that bats are unlikely to have fossilized.

So it's not a "big hole" in evolutionary theory, but a lack of information on the evolutionary history of one lineage.

That said, there are a couple of ways in general that structures like wings evolve.

1. Exaptation. This is the most common. In this the feature evolves for something else and then also proves useful for the function it is used for now. Both insect and bird's wings are examples of exaptation. Insect wings for heat exchangers and birds for being able to run up steep (nearly vertical) surfaces.

For bats, the membranes would have been useful for gliding, so they could glide from tree to tree or rock to rock and collect insects in the air. This would be food source that other shrews wouldn't have access to. At the point where the membranes were doing well as gliding would also be the turnover point for flying.

Notice that the bat's wing is also connected to the hindlimb. Which is the same type of structure that the flying squirrel has. So right there you have a transitional to a bat in a living organism."